A reciprocating gasoline engine, which is mounted as an example of an internal combustion engine in an automobile, is mounted with a variable valve train apparatus in which the phase or the opening/closing timing of an intake valve or an exhaust valve and the lift of the valve are changed for emission control or in order to reduce fuel consumption.
The variable valve train apparatus of this type has a structure such that the characteristics of the intake valve and the exhaust valve are altered by replacing the phase of a cam formed on a camshaft with a reciprocating cam of which a base circle interval and a lift interval are continuous with each other.
Many of structures that are used to alter valve characteristics are mechanisms in which the posture of the reciprocating cam is changed based on a rocking displacement of a control shaft, and the ratio between the base circle interval and the lift interval replaced by the reciprocating cam is varied based on this change. Thus, the lift and the opening/closing timing of the intake valve or the exhaust valve are variable (see Jpn. Pat. Appln. KOKAI Publication No. 2003-239712, for example).